Well, as noted before, I wasn't convinced by their analysis having done the calculation so I kept looking and found another white paper; this one by EPA
It draws the same conclusions I did--
"Phase separation, however, generally only occurs when liquid water (as opposed to water vapor) is introduced to the fuel system. If tank vents are left open, either in the engine being operated, or at a fuel distribution station, water can enter the fuel system in the form of rain (or spillage, etc.) or through the air in the form of moisture. Also, since conventional gasoline absorbs very little water, there is often a layer of water present at the bottom of a filling station tank normally used to store conventional gasoline (water is more dense than gasoline, and will therefore sink to the bottom). Before an oxygenated gasoline is added to such a storage tank for the first time (particularly ethanol-blended fuels), this water must be purged from the tank to prevent the water from removing any ethanol from the fuel.
Since the solubility of water in both gasoline and air decreases with a decrease in temperature, water can enter a fuel system through condensation when the atmospheric temperature changes. For example, assume a tank containing conventional gasoline contains only one gallon of fuel. Assume also that it is closed while the outside temperature is 100 degrees F with a relative humidity of 100 percent. If this tank is left sealed and the temperature drops to 40 degrees F, water will likely condense on the inside of the tank, and dissolve in the fuel. In order for enough water to condense from the air to cause gasoline-water phase separation, however, there must be approximately 200 gallons of air per gallon of fuel over this temperature drop (100 to 40 degrees). Since oxygenated fuels can hold even more water than conventional gasoline, it is even more unlikely that enough water will condense from the air to cause gasoline-water phase separation."
The 200:1 ratio almost precisely duplicates my earlier estimate...I just quoted it over a differing volume and in alternate units. I did note that while I hadn't computed it, the 3.8 tsp measurement your reference used is referred to in this document but they mis-computed/mis-typed the percentage in the 0.05%; it is 0.5%.
So, anyway, the problem of phase separation in E10 of initially clean fuel in a clean tank occurring owing to moisture condensation from the air introduced alone is simply a non-issue.